Treatment of petroleum hydrocarbons.



R. P. BACON & G. W. CLARK. TREATMENT OF PETROLEUM HYDROGARBONS.APPLICATION FILED MAY 6, 1912.

1,482. Patented June 23, 1914.

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RAYMOND FOSS BACON AND CLINTON W. CLARK, OE PITTSBURGH, PENNSYLVANIA.

TREATMENT OF PETROLEUM HYDROCARBON S.

Specification of Letters Patent.

Patented June 23,1914.

To all whom it may concern:

Be it known that we, RAYMOND Foss BA- CON and CLINTON W. CLARK, bothresiding at Pittsburgh, in the county of Allegheny and State ofPennsylvania, and both citizens of the United States, have invented ordiscovered certain new and useful Improvements in the Treatment ofPetroleum Hydrocarbons, of which improvements the followingis aspecification.

Our invention relates to the treatment of petroleum hydro-carbons, andits object 1s to increase the yield of gasolene from such mineral oils.

Ofthe gasolene now used for internal combustion engines and likepurposes, by far the largest part is obtained by the fractionaldistillation of crude oil under substantially atmospheric pressure, theout sold as the best gasolene ranging usually from boiling point ofapproximately C. to 150 C. I The supply thus obtained, has, both becauseof the increasing demand for gaso lene and because of the falling off ofthe supply of petroleum, proved to be "inadequate. Therefore, morespecifically stated, the object of our invention is to provlde a methodfor converting into gasolene petroleum hydro-carbons from which theusual gasolene component has already been removed by fractionaldistillation, or hydrocarbons ,which do not originally contain gasolene.

We have discovered that such low boillng point hydrocarbons as are usedas gasolene' may be obtained from hydro-carbons having boiling pointsabove that ordinarily used as asolene by distilling the high boilingpoint ydro-carbons under pressure; and further, we have discovered that,within certain approximate limitations of pressure, the yield otfgasolene thus obtained will be materially greater than when thedistillation isoffseted under pressures above and below suchlimitations; and, still further, we have ascertained that, aside fromthe lower yields of gasolene, the economic conditions of operation areprejudicial when effected both above and below such limitations ofpressure. As far as the lncrease 1n gasolene 'yieldis concerned, ourdiscoverystated in terms of pressures and boiling point temperatures ofthe hydro-carbons, is that a mixture of hydro-carbons of. boiling pointsranging from about 30 to 150 C. at atmos= pheric ressure, andhereinafter referred to ,as low iling point hydro-carbons, may beobtained in relatively large quantities from hydro-carbons ofboilingpoints ,of' about 250 C. and upward at atmospheric ressure, andhereinafter referred to as liigh boiling point hydro-carbons, bydistilling such big boiling point hydro-carbons at apressure rangingfrom about 100 to 300 pounds per square inch, and subse uentlydistilling by fractional distillation t e distillate thus obtained.

Not only are large quantities of low boiling-point hydro-carbon obtainedby distilling high boiling-point hydrofearbons at a pressure rangingfrom about 100 to 300 pounds per square inch, but the quality, also, ofthe lowl boiling-point hydro-carbons thus obtained is materially betterfor commercial purposes that that obtained by distilla tion at pressuresbelow 100 pounds. That is to say, of the two hydro-carbons, namely,saturated hydrocarbons which are deodorized and desirable commerciallyand un-- saturated hydrocarbons which have the opposite characteristics,the percentage of the former, as compared to the latter, is mate-'rially greater when distillation is effected at pressures above 100pounds than at pressures below it, and is substantially a con- 85 stantquantity at distillation pressures above about 100 pounds. Consequently,the subsequent refining loss, due to the presence of the unsaturatedhydrocarbons, which yield tar by the action of the refining acid, ismaterially lessened, our practice showing that this loss, which issubstantially uniform with gasolene resulting from distillation at 100pounds pressure and upward, increases tillation at pressures rangingdownwardly from pounds.

It will be understood that in practising the invention, the operatorwill, in establishing the pressure prevailing within the still withinthe described range, likewise provide for such rate of distillationaswill give at least the minimum proportional yield of low boilinghydrocarbons desired, which yield, for commercial purposes, may be takenat say 18%, by volume, of saturated hydro-carbons.

Other conditions being equal, the rate of distillation will depend uponthe temperature, and this is within the control of the operator who willdecrease it should the percentage of low boiling point hydrocarbons, atthe established high pressure, fall below the optimum.

. mately 300 pounds is a prejudicial factor.

In determining the approximate lower limit of 100 pounds pressure persquare inch we find that, when high boiling point hydrocarbons aredistilled at a pressure below about 100 pounds, there is a relativelysmall yield of low boiling point hydro-carbons as compared with thatobtained by distillation at a pressure above 100 pounds, all otherconditions being the same. Furthermore, such yields of low boiling pointhydro-carbons as may be obtained at a pressure below about 100 poundsare effected only at such sacrifice of time and fuel as to renderworking at such low pressures uneconomic and impractical. In determiningthe upper limit of about 300 pounds per square mch, we find that abovethis distillation pressure there is not only a dropping off of thepercentage of obtainable low boiling point hydro-carbons, but that thestill becomes coated with coke so rapidly that its heat conductivity isdiminished and there is a constant liability of its blowing out. Also,theloss of hydro-carbons through gasification when distilling atpressures above approxi- The temperature at which our method may bepractised depends, of course, upon the character of the high boilingpoint hydro-carbons treated. The temperature in each instance will besuch as to keep the mass, which is being distilled, under a pressure offrom about 100 to 300 pounds. As an example of the temperature which maybe required We find that a reduced Oklahoma petroleum (such petroleumhaving had its gasolene and kerosene components removed from it) distilsunder a pressure of about 200 pounds at a temperature ranging from about350 to 500 C. In order to obtain the desired low boiling pointhydro-carbons from the distillate thus produced, such distillate issubjected to the ordinary fractional distillation at substantiallyatmospheric pressure, subsequently to the distillation under pressure. 4

By the complete process as now described we have been able to obtain asmuch as 42% of gasolene, that is, hydro-carbons boiling at atemperatureranging from about-30 to 150 C. at atmospheric pressure, "fromhydro-carbons which before being subjected to the treatment of ourinvention contained no low boiling point hydro-carbons. Such increase inthe yield of said low boiling hydro-carbons is not nearly so great whenthe mass of high boiling point hydro-carbons is first heated for asubstantial length of time in a closed still or other receptacle to apressure between 100 and 300 pounds per square inch, and subsequentlydistilled at about atmospheric pressure, as when the distillation iseffected under the prescribed limitations of pressure. We do not hereinlongitudinal section showing somewhat'dia grammatically an apparatuswhich may be employed in the practice of our lnvention.

The still 1 is connected, as bypipe 6, to a suitable source of oilsupply, and has a pipe 7 extending from its upper portion through acondenser 2 to a receptacle? A gage for showing the pressure isindicated at 4, and a valve 5 for regulating the pressure is placed atany desired point along the plpe 7. In operation the higl'i boilingpoint hydrocarbons will preferably be fed continuously to the still 1,and .the temperature of the still contents will be suitably regulated tokeep the pressure therein between 100 to 300 ounds.

e claim as our invention:

1. The herein-described. method of pro:

ducing saturated gasolene hydrocarbons, (z.

e. hydrocarbons having boiling points ranghydrocarbons of a minimumvolume ofsubstantially 18% of the distilling charge.

- 2. The herein-described method of 'producing saturated gasolenehydrocarbons,

(2'. c. hydrocarbons having boiling points ranging from about 30 C.to150 O. at atmospheric pressure), which consists in simultaneouslydecomposing and distilling, under a pressure ranging from 100to300pounds per square inch, petroleum hydrocarbons having a boiling'point ofabout 250 C. and upward, the operation'being conducted at a rate to givea yield of saturated gaso lene hydrocarbons of afminimum volume ofsubstantially 18% of the distilling charge, and subsequently'treatingthe distillate. so obtained for the separation of the saturated gasolenehydrocarbons.

In testimony whereof we set our hands.

RAYMOND Foss BACON. CLINTON w. CLARK; Witnesses:

Roy H. BRowNLE J. M. ELIAS.

have hereunto copies of this patent may he obtained for five eenteeaeh,by. addressing the "Commissioner 0; mum,

Washington, D. 0." I

